1. Field of the Invention
The present invention related to formats for information storage systems.
2. Related Art
All storage devices require a method for protecting and organizing data so that the correct data can reliably be retrieved as desired from a host system. The definition for doing this is referred to as the logical format.
Holographic storage presents many new challenges for the development of a logical format that haven't been dealt with before in other storage technologies. In holographic data storage, the basic unit of storage is a data image which is a 2 dimensional array of light and dark pixels with light pixels usually representing 1's and dark pixels usually representing 0's. This image is recorded into the media as 3D interference patterns that can be reconstructed during readout. An image can have thousands or millions of information symbols. This contrasts drastically with current conventional storage technologies that store and read back a few symbols at a time either magnetically or optically. These devices may read data back in parallel on multiple tracks, but at most, only a few or 10s of symbols at a time.
For holographic data storage, recordings are interference patterns between a data beam and reference beam which are captured in some kind of holographic medium. The act of reading requires an incident beam that is a recreation of the reference beam to illuminate the recorded area. This reconstructs an image of the original written image. Some types of media have an issue where exposure to light prior to data recording uses up some or all of the medium's dynamic range, rendering recording difficult to impossible. A key feature of this logical format is its ability to ensure that unexposed areas of the medium are not exposed prior to recording.
Since the configuration of holographic data is radically different than the way it is stored in current storage technologies, there exists a need for a logical format for holographic storage that is able to protect the data to ensure the reliability and that is able to organize the data sot that the correct data can be addressed and read back.